While bigamy technically means the act of taking a second spouse while still legally married to a first (in cultures that enforce marital monogamy), in practice it also refers to people who have a whole series of such fraudulent marriages, a classic example being the sailor with a wife in every port. (The closely related word bigamist is the person who commits this act.)
The original meaning "two+spouse" has become "(two or more)+spouse". Not a huge change but a change nonetheless. A bicycle with three wheels is no longer a bicycle but a bigamist with three spouses is still a bigamist.
Dictionary cites:
bigamist (n.)
"one who has had two or more wives or husbands at once," (Etymonline, emphasis added)
"A man was charged with bigamy for being married to 17 wives." (Sample usage from oxforddictionaries.com)
(noun) unlawful marriage, illegal marriage, multiple illegal marriages, multiple spouses, marrying multiple partners, marrying multiple wives, marrying multiple husbands (Burton's Legal Thesaurus, Android app, retrieved 2018-06-26, emphasis added.)
A web search for the term serial bigamist pulls up a fair number of newspaper articles about people with multiple concurrent fraudulent marriages. Grammatically the term doesn't make sense, unless the word refers to the pattern of deception and not the specific state of having exactly two spouses. (And note that I have not been able to find a reputable dictionary that covers this usage, but mainstream newspapers from multiple parts of the English-speaking world do use it.)
(Bigamy is distinct from polygamy, whether legal or not, where a man has multiple wives with the knowledge and relative consent of all parties. Rarer still is polyandry where one woman has multiple husbands, best known from impoverished areas where a set of brothers may share one farm and one wife. Both differ from modern polyamory where consenting adults create individualized rules about long term relationships.)
Newspaper usage:
Serial bigamy is a lot more lucrative than it used to be. Immigrants looking for green cards will pay sham spouses thousands of dollars for an “I do,” said one law enforcement source [...] (New York Post, 2005-04-12)
The downfall of a serial bigamist and conman (Irish Examiner headline, 2012-03-08)
Serial Bigamist Pleads Guilty (Toronto Sun video clip title, 2018-02-23)
Multiple Bigamist Leaves Court (BBC photo caption, 2009-07-27)
Bronx Multiple Bigamist: Woman Caught With Ten Marriages, Only Four Divorces (Headline, The Inquisitr, 2005-04-10 (Note: better known as a source of scandal and gossip than news))
- Polyandry (There is a wealth of fascinating academic information about many patterns of polyandry online, but newspaper articles seem better for depicting language usage than technical papers, and they focus on the fraternal form):
Polyandry is still widely prevalent, a practice once common in Tibet. Brothers share a single wife, and it seems to create little domestic discord. (The Tribune (Chandigarh, North India) 2002-04-21)
They practice what is known as fraternal polyandry -- where the brothers of one family marry the same woman. Why? Tradition and economics. (CNN, 2008-10-24)
Definitions (all from dictionary.com) :
- bigamy : noun (1) Law. the crime of marrying while one has a spouse still living, from whom no valid divorce has been effected.
- polygamy : noun (1) the practice or condition of having more than one spouse, especially wife, at one time.
- polyandry : noun (1) the practice or condition of having more than one husband at one time.
- polyamory : noun (1) the practice or condition of participating simultaneously in more than one serious romantic or sexual relationship with the knowledge and consent of all partners.